In such receivers, as -well as in certainother optical apparatus'to Which'the concepts of the invention are applicable, it .is necessary .to y-elect precisely controlled relative vmovement between the cathode-'ray tube (or other vdevice upon Whichan image is presented) and certain optical elements which dene an optical axis. 'Such movement is required, if proper focus is to vbe achieved upon va viewing surface or screen. A1- though not limited to use therewith, the concepts of .this invention are of particular utility-in projection television receivers utilizing a Schmidt type reflective optical system, that is, receivers which include a mirror and a lens, or correcting plate, effective to provide correction `for an aberration introduced by said mirror. A cathoderay tube is arranged-between the mirror and lens, Which-latter two elements dene an optical axis.

In the patent to vIngo ;L..S,tephan, bearingiNo. 2,424,513, granted `July 22, 1.94.7, and assigned to the assignee of the Iinstant invention, kthere :is disclosed and claimed an advantageous'type of focusing apparatus which, essentially,.fcomprises: mechanism for angularly adjusting a screen about a predetermined point as a center of pivotation whereby properly to orientsaid screen with respect to an optical axis, said point lying substantially in said screen, the aforesaid mechanism takingthe form of means providing a pair ofindividual rotational axes passing through said point in substantially right-angularlyrelated directions and about Whichsaid'screenmay'be adjusted selectively.

My invention has to do with improvements in apparatus of this class.

While the construction With Which the abovementioned patent is concerned has proven highly advantageous in practice, embodiments of that invention are found to be subject to certainoperationaldimculties and disadvantages, the elimination of which is the concern of the present in- Vention.

For example, :in the prior .apparatusthe r"elements to be manipulated, during a focusing loperation, .were lnot so disposed as =to realize the :0ntimum convenience of adjustment and, frequently,adjustments could 'not bemade Without placing the hands Ain theppath oflight projection. Additionally, therhighestdegree of independence of adjustment about the aforesaid axes yis not always achieved, in the prior focusing arrangement, since at least certainlembodiments of that constructionare characterized bythe presence of locking instrumentalities which `are-set, lfollovving adjustment of the .tube about one axis, and priorzto adjustment about the other axis.

With Athe foregoing in mind, it is a primary object of the persent'invention to provide a simple and inexpensive adjustable mounting -for cathode-ray tubesor other `devices having a primary image Ascreen-by 'the use of which mounting such'tubessmay be readily and precisely oriented With respect to an optical .axis in such manner as to accomplish'the necessary focus adjustmentsin ythe simplest possible manner.

.More particularly, the invention has as an object the provision of Schmidt type `projection ,apparatus including a cathode-ray tube enclosed Within a dust-,resistant housing, in which apparatus ithe tube screen maybe given any threedimensional yangular adjustment, Within defined limits, andwhich apparatus is of such a nature that `all*adjustn'xerltsmay'be accomplished'by effecting'simple rotary movements of control elements disposed ina single readily vaccessible location exterior of the housing.

Amadditional important .objectfof the invention vresidesin the Yprovision of `suchzfocusing apparatus in which -the location `of `the adjusting elements is such that all -ia'djustments can be made without placing the hands Within the path of `light projection, and-in which apparatus the component parts aresofshaped and disposed that they introducefnofsigniiicant.light loss.

` It is a furtherieaturefo'f the constructionjthat nontools are required duringthe adjustment operations, and' ythat :all adjustments are vernier in nature.

The invention ris further characterized `in `that the stabilityof `the control elements-following adjustment'thereof-is such that it is:not neces sary toy employ' locking ydevices lwhich must be released pricrito:re-manipulation of said elements. As :willbeappreciatedsuch locking devices are dsa'dvantageous,inthat theyptend to complicate the adjustment operations, and-alsc'in that failure'vtosecure themfproperlymayresult in drift from fthe optimum position tof. adjustment.

In commonfwith 'the apparatus disclosed and claimed in the said Stephan patent, the device of this invention provides for selective adustment of the tube screen about either :of two rightangularly related axes. A third axis, coinciding with the :longitudinaliaxisof the tube,.extends generally perpendicular to both the tube screen and the pair of axes aforesaid, and also passes through the geometrical center of the tube screen, or other predetermined point selected in the latter. Axial movement of the tube may be effected along this latter axis. By individually adjusting the tube screen with respect to the above-described axes, it is possible to achieve resultant components of adjustment movement of the screen in all planes, that is, universal or three-dimensional adjustment of the screen is provided.

The manner in which the above-mentioned objectstogether with certain advantageous convstructional features of the present inventionare realized, may best be understood by making reference to the following description and the accompanying drawings in which there is described and illustrated a4 preferred embodiment of this invention.

In the drawings:

Figure 1 is a somewhat diagrammatic, perspective representation showing the essential elements of the invention and illustrative of the mode of operation thereof;

Figure 2 is a sectional view taken through the longitudinal-vertical mid-plane of apparatus constructed in accordance with the invention;

Figure 3 is a sectional view taken in the direction indicated by the line 3 3 of Figure 2;

Figure 4 is a sectional view taken through the longitudinal-horizontal mid-plane of the apparatus, that is, taken in the general direction indicated by the line 4 4 applied to Figure 3; and,

Figure 5 is a perspective illustration showing a portion of the apparatus on an enlarged scale.

Although the following description and the accompanying drawings are fully illustrative of my improved focusing apparatus, per se, and indicative of the preferred mode of operation, it is to be understood that the apparatus is preferably used in conjunction with projection television equipment of the type completely disclosed in the aforesaid patent to Stephan to which reference may be made in the event that further elucidation of the improved apparatus, in situ, should be desired.

First making detailed reference to Figures 2 to 4, the class of projection system to which the invention is most applicable includes a cathoderay picture tube Ill having a uorescent screen or target area II in the forward face thereof, the projection tube being adapted for cooperation with aconcave mirror and a lens, or plate, congured to correct for an aberration introduced by the mirror. Since the invention may be well understood without reference to the mirror and the correcting lens, per se, these elements are not illustrated in the drawings, but it is to be understood that, in accordance with known practice, the tube IIJ, the mirror and the correcting plate are arranged as a unitary assembly enclosed in a dust-resistant housing indicated, generally, at I2. When the apparatus is in use, the concave mirror is received within an annular seat or collar portion I3 which is disposed at that end of the housing I2 which confronts the face of the tube IEB. As will be recognized, a co-rrecting lens of the type employed herein surrounds the neck portion of the tube and ris held against the opposite end of the housing I2 by means of a plurality of adjustable retaining devices two of which are illustrated at I4, in Figures 2 and 4.

Since such a Schmidt system is well known in optics, and since the invention is concerned with 4 the manner in which the tube I 0 is adjustably supported within the housing I2, detailed description of the system is not necessary herein. However, if further description of such projection television'apparatus is desired, reference may be had to the above-identified patent to Stephan.

In such projection equipment, the cathode-ray tube screen must be properly orientedY with respect to the optical axis of the system in order that all portions of the projected image may be focused properly upon a viewing screen (not shown). Also, not infrequently, the viewing screen is angled with respect to the optical axis of the Schmidt system which angularity, if compensation is not made therefor, introduces an out-of-focus effect.

In particular accordance Iwith the present invention, both the general focus requirements, and correction for out-of-focus effects which are introduced if the viewing screen is angled with respect to the optical axis, are taken care of by a novel mounting providing for ready and accurate three-dimentional adjustment of the tube screen with respect to the optical axis, said axis being represented at I5 in the drawings. As will be understood, the aforesaid concave mirror and the correcting lens define the optical axis.

To provide for such focus requirements, and in common with the structure disclosed and claimed in the Stephan patent, supra, the tube IU is mounted for rotational movements about a pair of axes passing, in substantially right-angularly related directions, through a predetermined point which is preferably in approximate coincidence with the geometrical center of the fluorescent screen of the tube. This point clearly appears in the drawings, and bears the reference character I5, the aforesaid pair of axes being represented at X-X and Y-Y, in which connection see particularly Figure 1. A Z-axis, being the longitudinal axis of the tube, also appears in the drawings, in which connectionreference may be made to Figure l. In other views of the drawings the Z-axis is shown in such position that it coincides with the optical axis I5, however, in practice these two axes will frequently be in only approximate coincidence.

To provide for precisely controlled movements about the three axes aforesaid, and in accordance with the foregoing statements of object and advantage, the tube I0 is carried by a yoke member II the free leg portions of which straddle the tube face in the general plane thereof and are mounted upon the housing I2 at spaced points defining the axis identified at X in the drawings. `To this end, the housing is provided with aY pair of confronting bosses I 8-I8 (see Figures 3 and 4) through which pass studs I 9-I9 which effect pivotal securement of the yoke I'I to the housing lil and provide for pivotal movements of said yoke about the said X-axis.

Carried by a rearwardly extending portion 20 of the yoke I'I is a member or plate 2| which is journalled for swinging movements in a plane generally paralleling the optical axis, through the agency of a stud 22 which is fixedly secured to the yoke I1, any suitable means being used for this purpose. The essential features of this arrangement may be Well understood by making particular reference to Figures 1 and 2, in which connection it is to be noted that the swingable plate or member 2I underlies the portion 20 of yoke I1, and thatrsaid plate supports the tube I0, as will more fully appear inwhat follows.

The stud 22`is'so disposed upon yoke I1 that 21 traders;j

it' defines the axis Y-Y,Vwhich axis passes through the center point l of the tube screenandA intersects axis X-X, regardless of!v the'` respect to the yoke, at a point so disposed thatl the swinging movements of said plate take place about the Y-axis regardless of the position of the yoke.

Now making reference to the manner in which the plate 2| provides support for the tube I0, it will be observed, from Figures 2 and 4, that a clamp 23 surrounds the neck of the tube, thereby supporting the latter, and that this clamp is provided with an upwardly extending arm 24 which terminates in a plate 25. Plate 25, in turn, is carried by swingable plate 2|, in the manner now to be described.

As best seen in Figures 2, 4 and 5, plate 2| is provided with a downwardly turned ange 26 and with a pair of downwardly turned ear portions 2'1-21. This ange, and the said ear portions, are apertured to receive a pair of guide rods 28-28 which are freely slidable in the apertures and which pass through apertured flanges 29-29 upstanding from the plate 25. FiXedly secured in flange 26, and lying midway between the guide rods 28-28 is a threaded shaft 30' Shaft 3i) (see particularly Figures 4 and 5). also passes through anges 29-29, of plate 25 and through an angle bracket 3| (Figure 4) fixed to the free ends of guide rods 28-28' as by means of nuts 32--32. The nuts 32 cooperate with a shouldered portion formed adjacent the free end of the guide rods in such manner as to secure the tube-supporting plate 25 to the guide rods, which rods, as set forth above, are slidable within the flanges formed upon swingable plate 2|. The angle bracket 3| has an offset portion spaced from the confronting face of flange 29, andbetween this angled portion and the said l confronting face lies a screw-threaded control element, or adjusting member 33, which is co-V operable with the threads provided upon shaft 3|) to provide for reciprocatory movements of the tube-supporting plate 25, and therefore of the guide rods 28-28, with respect to the pivotally mounted plate 2|. Such re'ciprocatory movements, of course, result in similar movements of the tube it) along the axis Z-Z.

As will now be understood, clockwise rotation of the control element 33 causes said member to bear against the upturned flange 29 and, by virtue of the screw-threaded engagement of element 33 with the threaded rod 3|), results in movement of the plate 25, and therefore of the tube |41, in a direction toward swingable plate 2| and along the axis Z-Z. Similarly, counterclockwise rotation of element 33 causes said element to bear against the inside surface of the recessed portion of angle member 3|, and thus results in moving the plate 25 away from the swingable plate 2| and in consequent movement of the tube backwardly along the axis Z-Z. A

pair of spring washers 33a and 33h serve to take up any backlash between the threaded portions of shaft 33 and element 3-3, said washers also being effective to prevent inadvertent rotation of element 33.

Now making more detailed referenceto the manner in which the yoke and consequently tube-'- i'u', may' be adjusted about the axis it 'will be seen (Figure 2) thatl the stud 22 car-J' ries a rod 34 which is pivotally secured to saidl stud, as at 35, and extends ba'ckwardly through.

an apertured extension 3G of the housing |2f.

The free end of rod 34' is threadedA and, throughl the agency of a' control element 3i and anangle bracket 331 (said element and bracket-as well. as the spring washers associated` therewithbeing essentially similar to elementso33 and 3L already described) it is possible to effect precise,

micro'metri'c adjustment of the tube l0 about the axis X-X, by effecting swinging movements of the yoke I'!y about the studs |9-I9 which serve to secure sa'idfyoke to the housing l2. During such swinging movements the plate 2| remains fixed with respect to yoke i7 and, therefore, both said plate 2| and the tube Iii` are carried with the yoke during the swinging movements aforesaid..

Pivotal movements of the tube about the axis Y-Y are provided for as follows.

As' appears to best'advantages in Figures l4- and 5, a third adjustable control element39 extends transversely of the swingable plate` 2|, said element 39 being secured to a,- screw-tlireaded rod 40 journalled for rotary movements in a ipair of flanges 4|4|, which latter extend downwardly from the extension 20 of yoke I1. Again, spring washers 39a and 39h are used in the manner and for the purposes already stated with respect to washers 33al and 33D.

As clearly shown in Figure 5, the rod 40 passes through a block 42, being in screw-threaded engagement therewith, and overlying said block 42 is a swingable link 43 pivotally secured to the plate 2| by means of a stud shown at 44. Block 42 carries an upwardly extending key 45 which engaged in an aperture provided in swingable link 43. Rotary movements imparted to the control element 39 serve to rotate rod 40 and thus cause reciprocation of the block42 along said rod 40. The reciprocatory movements of the block 42 are imparted to the plate 2 I, through the swingable link 43, thus causing the link to be moved` about the stud 22 carried by yoke I1. `The movements of block 42 are translational, whereas the movements of -plate 2| are rotational, but

free transfer of motion between said block 'andplate is accomplished through the agency of the aforesaid swingable link 43.

Thusywhen it is desired to adjust the tube vscreen about the axis Y--Y, precise, micrometric ,adjustmentl movements are' imparted to ithe swingable plate 2|, which plate serves to support tube l0 in themanner described above. f

To provide support for the swingable plate 2 l', in addition to the support afforded by Ith'einter'- connection of said plate with the stud 22, the ,plate has an elongate aperture l4S through which passes a screwmember 41 (Figure 4.) which serves t'o support a washer 48. The said washer'bears against the under surface of the plate 2 l, whereas the screw-threaded member v4'!V extends through the lost motion connection means aff ordedv by slot 46 and is engaged in extensionZ- of yoke Itis particularly tobeobserved that the-apparatus of the invention is not onlyY of such aA readily accessible location. As shown in Figure 3, a cover member 49 is preferably secured to the housing I2, as at 50, serving to minimize the eiects of dust and moisture which mightotherwise gain entrance to the housing I2 through the aperture provided in the upper portion thereof. All adjustments of the tube may be made without interfering with the path of light projection, and it is to be noted that the component parts of the apparatus are so shaped and disposed that they introduce no significant light loss.

With the foregoing detailed description in mind, the diagrammatic showings of Figure-1 will illustrate the simplicity and accuracy with which the tube may be focused. Rotation of the control element 31, and consequent pivotation of yoke l1, is effected until the upper and lower portions of the image appear in proper focus upon the viewing screen (not shown). When this conditions has been reached, manipulation of the control element 39 serves to swing the plate 2|, and therefore to move the tube l0, about the axis Y-Y until a position is reached in which the side portions of the primary image are also projected into "good focus upon thel viewing screen. All of the focusing adjustments may be made Without the necessity of gaining access to the housing and, since the tube is moved selectively Vabout individually defined*v axes, the apparatus is extremely stable during the focusing adjustments.

Manipulation of the control element 33, and consequent adjustment of the tube along the axis Z-Z, may be used to insure that pivotal movements of the tube about either the X-axis or the Y-axis will, in fact, take place about the vsaid ,predetermined point lying in the tube screen. Following adjustment of the tube about the X and Y axes, it may atv times be advantageous to recheck for most accurate focus, by trimming the tube slightly along the Z-axis.

I claim:

l. For television apparatus and the like including a primary image screen, mechanism for angularly adjusting said screen about a predetermined point as a center of pivotation whereby properly to orient said screen with respect Vto an optical axis, said point lying approximately in said screen, said mechanism including: means providing for selective rotational adjustment of said screen about either of Va pair of individual axes passing through said point in substantially right-angularly related directions and lying subj. stantially in a common plane, said last-mentioned means comprising; structure mounted for pivotal movements about one of said axes, a'member carried by said pivotally mounted structurefand movableV therewith, said member also 'having freedom Vfor pivotal movements about the other ofsaid axes and independently of said structure, support means carried by said member and pro- Y viding Supportfor the aforesaid screen, and a providingfor selective rotational adjustment ofsaid screen about either of a pair of individual axes passing through said point in substantially right-angularly related directions, said lastmentioned means comprising; structure mountedv other of which is carried by said structure and drivingly associated with said member, said control elements being selectively operable to eiTect micrometric adjustment of said structure and said member about the associated'axes.

3. For television apparatus and the like including a primary image screen, mechanism for angularly adjusting said screen about a predetermined point asV a center of pivotation whereby properly to orient said screeny with respect to an optical axis, said point lying approximately in said screen, said mechanism including: means providing for selective rotational adjustment of said screen about either of a pair of individual axes passing through said point in substantially right-angularly related directions and lying substantially in a'common plane, said last-mentioned means comprising; structure mounted for pivotal movements about one of said axes, a'member carried by said pivotallymounted structure and movable therewith, said member also having freedom for pivotal movements about the other of said axes and independently of said structure, support means carried by said member and providing support for the aforesaid screen, a pair of control elements one of which is drivingly associated with said structure and the other of which is drivingly associated with said member, said control elements being selectively operable to effect micrometric adjustment of said structure and said member about the associated axes; and means for moving said support means translationally with respect to said member whereby to effect movements of said screen in a direction generally normal to said plane. 4. Apparatus in accordance with claim l, and further characterized in that'said structure includes mounting-means aligned with one of said axes, and said member comprises a plate mounted for swinging movements about said mounting means.

5. Apparatus in accordance with claim 4, and further including means providing for micrometric adjustment of said screen with respect to said plate in a direction generally normal to said plane.

6. Apparatus in accordance with claim 1, and

- further characterized in that said structure comprises a generally U-shaped frame the ends of which are mounted for pivotation about spaced points defining the associated axis.

Y 7. For television apparatus and the like including a Ycathode-ray tube having a primary f image screen, mechanism for angularly adjusting said tube about a predetermined point as a center of pivotation whereby properly to orient said screen with respect yto an optical axis, said' point lyingapproximately in said screen, said mechanism including: means providing for se-Y lective adjustment of said screen about either of a pair of individual rotational axes passing through said point in substantially right-angularly related directions and lying substantially in a common plane, said last-mentioned means comprising; a yoke having leg portions which straddle the face of said tube in the general plane thereof and are so mounted as to provide for pivotal movements of said yoke about one of said axes, a member carried by said yoke and movable therewith during movements o the yoke about the said axis, said member also having freedom for ypivotal movements about the other of said axes and independently of said yoke, said member further providing support for said tube, and a pair of manually operable control elements one of which is adapted to react against fixed structure and is drivingly associated with said yoke and the other of which is adapted to react against said yoke and is drivingly asso- Y ciated with said member, said control elements being selectively operable to effect micrometric adjustment of said yoke and said member about the associated axes.

8. Apparatus in accordance with claim 7, and

further including a third control element for effecting micrometric movement of said tube with respect to said plate-like member in a direction such as to effect movements of the tube screen in a direction generally normal to said plane.

9. For television apparatusand the like including a cathode-ray tube' having an image screen, a housing, mechanism adapted to support said tube within said housing with freedom for angular movements about a pair of axes passing through the mid-point of the screen in substantially right-angularly related directions and in the plane of the screen, said mechanism comprising: a yoke pivotally mounted upon said housing and so disposed that the pivotal movements thereof take place about one of said axes; means carried by said yoke and adapted for eures ein guoddns oq eqnq pres Imm uorqoauuoo said means being movable with the said yoke during movements of the yoke about the said one axis, said means further being so pivotally secured to said yoke as to provide freedom for pivotal movements of said means about the other of said axes and independently of said yoke;

and a pair of control elements one of which isdrivingly associated with said yoke and the other of which is carried by said yoke and is drivingly associated with the said means, said control elements being selectively operable to eiect mi- 10 crometric adjustment of said yoke and said means about the associated axes.

10. For television apparatus and the like including a cathode-ray tube having an image screen, iixed structure including a housing, mechanism adapted for connection with said tube to support the same within said housing with freedom for angular movements about a pair of axes passing through the mid-po-int of the screen in substantially right-angularly related directions and in the plane of the screen, said mechanism comprising; a yoke having leg portions which straddle the face of said tube in the general plane thereof and are mounted upon said housing at spaced points deiining one of said axes, whereby to providefor pivotal movements of the yoke about the said one axis; means carried by said yoke and adapted for connection with said tube to support the same, said means being movable with said yoke during the movements of the yoke about the said one axis, said means further being mounted for swinging movements with respect to the yoke at a point so disposed that the swinging movements of said means take place about the other of said axes regardless of the position of the yoke; and a pair of manually operable control elements one of which is adapted to react against said xed structure and is drivingly associated with said yoke and the other-of which is adapted to react against said yoke and is drivingly associated with said means, said control elements being selectively operable to effect micrometric adjustment of said yoke and said means about the said axes.

FREDERICK E. RADMAN.

REFERENCES CITED The following references are of record in the file of this patent: